You are looking at the HTML representation of the XML format.
HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information.
<?xml version="1.0"?>
<api>
  <query-continue>
    <allimages gaicontinue="Barrendesert.png" />
  </query-continue>
  <query>
    <pages>
      <page pageid="2496" ns="6" title="File:20070219 rpgww.png" />
      <page pageid="2339" ns="6" title="File:400px-Unbalanced scales.svg.png">
        <duplicatefiles>
          <df name="Unbalanced_scales.png" user="Archmage" timestamp="2007-02-12T17:04:03Z" />
        </duplicatefiles>
      </page>
      <page pageid="2485" ns="6" title="File:Abstractmagicpostrank04.gif.png" />
      <page pageid="2480" ns="6" title="File:Advsignsoftheapocolypse.gif.png" />
      <page pageid="2762" ns="6" title="File:Alphabet common.jpg" />
      <page pageid="2761" ns="6" title="File:Alphabet griffonic.gif" />
      <page pageid="2209" ns="6" title="File:Alternate GURPS RP Gaera-2.png" />
      <page pageid="2074" ns="6" title="File:Anira Hates Boats by Lithaladhwen.jpg" />
      <page pageid="1431" ns="6" title="File:Ardam (Kai).jpg" />
      <page pageid="2558" ns="6" title="File:Bagaga.png" />
    </pages>
  </query>
</api>